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Canker Sores vs Cancer

Updated on June 16, 2022
Khushbu Gopalakrishnan Headshot
Written by Aaron Clarius
Medically Reviewed by Khushbu Gopalakrishnan

What are Canker Sores?

Canker sores, or aphthous ulcers, are benign mouth ulcers that can appear in several areas of your mouth. They aren’t contagious and usually resolve on their own within 1 to 2 weeks.

Canker sores can recur in some people. This condition is known as recurrent aphthous stomatitis (RAS). The causes of RAS aren’t fully understood, but they may include dietary issues, hormonal factors, and stress.1

While there isn’t a cure for aphthous ulcers or RAS, most cases aren’t severe, and they may become less frequent with age.1, 2

What Canker Sores Look Like

A canker sore will generally appear as a round spot with a white, gray, or yellow center and a red outline. 

Mouth Ulcer

What is Mouth Cancer?

Any part of the mouth can be affected by cancer. Some oral conditions, such as leukoplakia, may be precancerous.3

Tobacco use, alcohol consumption, and human papillomavirus (HPV) infection are major risk factors for mouth and throat cancer.4

Unlike canker sores, which tend to stop appearing as you get older, oral cancer risk increases with age. Men are also more at risk for mouth cancer than women.5

What Mouth Cancer Looks Like

Oral cancer can appear anywhere in or around the mouth. This includes the throat, tongue, inner mouth, and the inner or outer lips. It may first appear as a rough white or red patch or as a mix of white and red patches.

According to Dr. David Chen, DDS, “a canker sore is a temporary but annoying condition, which typically self resolves within 2 to 3 weeks. Mouth cancer, on the other hand, is a condition that does not self resolve and will continue to grow larger and larger in size if there is no professional intervention.”

Therefore, the duration of the ulceration is one of the distinguishing factors between the two conditions. If an ulceration persists for longer than 2 to 3 weeks, it may be more than just a canker sore.

Symptoms of a Canker Sore vs. Mouth Cancer

Canker sores and mouth cancer can be further distinguished by their accompanying symptoms. 

Canker Sore Symptoms

Canker sores are often painful and can cause a burning sensation in the hours leading up to their formation.1

The sores may become more painful when eating or drinking, especially if the food or drink is spicy, acidic, or abrasive. Because of this, severe cases of RAS can lead to poor nutrition and unhealthy weight loss.1, 6

Although RAS does not cause other symptoms, other types of oral ulcers can be caused by certain systemic illnesses, such as celiac disease.1, 2

Talk to your dentist or doctor if you’re experiencing any painful or unusual symptoms outside of your mouth. These include abdominal pain, chronic diarrhea, or ulcers elsewhere on your body.

Mouth Cancer Symptoms

Cancerous patches in the mouth may or may not be painful. Other possible symptoms of oral cancer include:

  • Difficulty swallowing
  • Painless swelling of one or both tonsils
  • A painless lump in the neck
  • A chronic cough, sore throat, or hoarse voice
  • Loose teeth
  • Ear pain

If you have sores or patches in your mouth for more than two weeks, or any other of the above symptoms, consult your doctor immediately.

How is Mouth Cancer Diagnosed? 

To diagnose oral cancer, your doctor will examine your mouth and may take a tissue sample for biopsy. The tissue will be examined in a lab to determine whether it contains cancerous or precancerous cells.

Your doctor may also use an endoscope (a small, lighted medical camera) and/or imaging tests (such as CT and other scans) to get a more complete picture.

Treatment for Mouth Cancer vs. Canker Sores

Treatment for canker sores and mouth cancer differ greatly. Treatment for oral cancer is more intensive. 

Canker Sore Treatment

Treatment for RAS aims to relieve pain and promote healing, as well as reduce the frequency and severity of the sores.

Good oral hygiene and a healthy, balanced diet can help manage canker sores. Sometimes the sores are caused by nutrient deficiencies and go away once the deficiency is addressed.1

Topical medications, such as anesthetics, antiseptics, and anti-inflammatory drugs such as corticosteroids, are sometimes prescribed for more painful or severe canker sores.

Mouth Cancer Treatment

The way oral cancer is addressed varies, and may include multiple avenues of treatment. The nature of treatment will depend on the location and extent of the cancer, overall health, and personal needs.

Treatment for mouth cancer may include:

  • Surgery to remove tumors
  • Radiation therapy
  • Chemotherapy
  • Targeted drugs, which may work in tandem with other treatments
  • Immunotherapy

These options may not be exclusive, and a combination of approaches may be necessary or preferred. You should discuss your options in depth with your doctor.

Quitting tobacco, moderating alcohol consumption, and taking precautions with sun exposure can all reduce your risk of head and neck cancer.7 You can also take steps to limit your risk of HPV exposure, such as HPV vaccination and safe sex practices.

Summary

Though canker sores and mouth cancer sometimes look similar, their symptoms differ. Canker sores tend to resolve within 1 to 2 weeks and are often somewhat painful. Oral cancer doesn’t resolve on its own and may not be painful at first.

If you have some type of sore or wound in your mouth that does not heal after 2 to 3 weeks, seek out a healthcare professional, says Dr. David Chen. This is a major distinguishing factor that rules out a canker sore.

Aside from that, a second but equally important point to remember is that if you have a lump or mass in your mouth that increases in size, even if it is not painful, you should still seek medical help,” he adds. “This is indicative that it is not a temporary condition with a bad trend.”

Last updated on June 16, 2022
6 Sources Cited
Last updated on June 16, 2022
All NewMouth content is medically reviewed and fact-checked by a licensed dentist or orthodontist to ensure the information is factual, current, and relevant.

We have strict sourcing guidelines and only cite from current scientific research, such as scholarly articles, dentistry textbooks, government agencies, and medical journals. This also includes information provided by the American Dental Association (ADA), the American Association of Orthodontics (AAO), and the American Academy of Pediatrics (AAP).
  1. Sánchez, J. et al. "Recurrent Aphthous Stomatitis." Actas Dermo-Sifiliográficas (English Edition), vol. 111,6 , 471-480.
  2. Altenburg, A. and C.C. Zouboulis. "Current Concepts in the Treatment of Recurrent Aphthous Stomatitis." Skin Therapy Letter vol. 13,7 .
  3. Parlatescu, Ioanina et al. “Oral leukoplakia - an update.Maedica vol. 9,1 : 88-93.
  4. Rivera, César. “Essentials of oral cancer.International journal of clinical and experimental pathology vol. 8,9 11884-94. 1 Sep. 2015
  5. "Oral Cancer Incidence (New Cases) by Age, Race, and Gender." National Institute of Dental and Craniofacial Research.
  6. Mouth cancer.” Mayo Clinic.
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